allan1010

1.2 volts is the nominal voltage UNDER LOAD. They will read higher when they're sitting there but that'll drop when you make them work. 1.225 volts is only one fortieth of a volt over the nominal voltage anyway, 1.335 is about a thirtieth of a volt. Even at 1.4 volts, a fifth of a volt that disappears under load is hardly life changing, ALL NiMH batteries exhibit these charateristics to an extent. Low internal resistance also has no bearing on voltage but rather power as it allows current to flow from the battery more quickly and allows the stabilised voltage of the battery to remain maximised.

More voltage? Are you sure and if so can you explain please? I didn't think it was possible for NiMH's to produce more than 1.2v per cell. Curious.....

I ditched the switch and now I just use a servo extension lead. That stays plugged into the receiver inside the radio box and the other end goes onto the battery. I just unplug it when I'm done.

If your shop says it's Ok then don't worry about it. But if it is gonna go wrong it'll most likely be from overheating so make sure that if it gets really hot you allow it to cool down for 5 or 10 mins. It'll cool down quicker if you leave the bodyshell off and/or maybe direct a fan across it on a table or something.

You already have the answer! Too much heat, which is generated by drawing more current through the esc than it can handle. Assuming there isn't another fault (like a short circuit or dry joint on the esc board) then putting a fan or heatsink on might help short-term but ultimately you'll burn the esc out.

If you have the 26cc Zenoah, CY or FG Power engine the settings are 1.25 turns for the low speed needle and 1.5 turns for the high speed needle, both out from fully closed. be careful if you close them that you just "bottom" them gently so you don't damage the needle tips. That diagram shows trhe correct carburettor. Before you mess with the needles take your spark plug out and see what colour the tip is. If it's still black from your forst very oily session, clean it off as shown and run it some more, look again. If it's still black you're running a little too rich on the mixture. But before I go through that with you, let me know about the plug first, after cleaning and running another 15 to 20 mins if necessary.

The battery capacity is irrelevant, it's just like putting a bigger fuel tank on your nitro. Voltage is important BUT lipos have extremely low internal resistance so they can provide their power at an extremely high rate. The 50A max and 15A continuous ratings on your esc are the key, but I don't know what your motor will draw on lipos so there's one way to find out...... If you know the figures for your motor you can work it out yourself, power (Watts)/ voltage (Volts) = current (Amps). Good luck.

Now you tell me! You didn't say you'd damaged it, just that iot was leaking. But you'd be surprised what modelsport will do as a "gesture of goodwill".

Ziggy, it's a 1200mAH battery on an 80mAH charger. A 12 hour charge will only put in a max of 960mA minus the heat & resistance losses.

If you can get a metal gearset for the servo you've got, fitting it is a doddle. As to the other, that's a lot like asking "which buggy should I buy" and everybody howls their favorite name LOL. I'm running the Hitec 5745 that came as stock in my marder and I haven't managed to damage it yet. It's also fast and waterproof. I'd suggest that the best one for the job is the Tonegawa, a whopping 65 Kg/cm of torque and built for professional use in special effects, remotely-operated vehicles etc. The downsides are the fact that it needs to be powered separately from the receiver and the £150 price tag.

NO!! That copper stuff ("Copaslip") is abrasive! It's great as an assembly lubricant for things like nuts & bolts that you want to tighten up but don't want to sieze, but it's no good for parts that move constantly like bearings or your throttle arm, it'll wear them out quicker. If the engine's only 3 weeks old I'd take it back or email whoever you bought it from. Tell them where the fuel is leaking from. They should replace the carb for you free of charge, unless you've done something to damage it while you were tuning it etc.

Dinky's right but you'll need to add 20 to 50% to the time to counteract the energy lost to heat & internal resistance when the battery is charging You won't do it any harm at all or overcharge it as long as the charger is less than C/10 (one tenth of the capacity of your battery), and yours is well under that. According to the calculations your charger will charge the battery from flat in 15 hours. By the time you add on 20 to 50% then any charge time from 20 to 24 hours will be fine. By comparison, my slow charger is 140mAH and the instructions suggest 1 hours charge (or 140mA) per 100mAH of battery capacity so you can see that this represents a 40% addition or overcharge, which falls within the 20 to 50% I mentioned. This overcharging on a trickle charger doesn't harm the battery because there isn't enough heat generated to do any damage.

It might work fine guys but be aware that it WILL affect your range. By hw much deoends on what proportion of a wavelength of wire you cut. If you have sufficient range after you've curt it then that's great.

There's no such thing as "nitromethanol". Apart from oil, the 2 other ingredients in nitro fuel are nitromethane and methanol. I don't have a link but I'd heard that oil helps with cooling. It makes sense too if you think about it. More oil in the formula means less actual combustible fuel and less heat from each combustiion cycle in the cylinder.

Are these the kind with the wire clip going through? If so we were just discussing this last weekend when a guy turned up with a mint used Hormann. There are so many applications for that exact joint it's unbelievable. Everything from largescale r/c's to old vauxhall chevettes & some astras, right through to Mercedes, Daf and Volvo trucks from 7.5 tonne to artic uses those on the throttle linkages!! I'd take one off and (even a plastic one) and take it to a proper motor factors (NOT Halfords, go to the guys that suply the auto and truck trade with parts). See if they can help. That's what we'll be doing. I thini the last metal ones I bought from Volvo Trucks in Darlington were cheaper than hobbythek's price but I know you can go lots cheaper again if you hunt around. That's what I'll be doing, meanwhile my plastic ones are doing great.

Two quick points, 1) The capacity of a battery cannot be determined by charging it. It will ALWAYS take more current to charge than it can hold because of internal losses and heat generated in charging. The hotter you get the packs, the more charging power you lose, sometimes significant amounts. To determine the capacity of a battery accurately you have to peak charge it then measure the discharge capacity at a rate that, again, doesn't heat the battery pack up. 2) I'm not a serious r/c racer but I did some club racing a long time ago before returning to r/c largescale. The thinking at that time was that, if, say, you were running 5 or 6 minute heats & races then any running time over and above that was just wasted potential in your car. You COULD have gone faster, turned a bigger gearing, higher RPMs from your motor or all of the above! So electrics were designed to mostly run for under 10 minutes, you might have got 15 minutes in a mild setup but compared to nitros, duration was their big limiting factor. I still can't see the point for racers in having cells that can last several heats on a single charge; isn't it better to save weight and just go with smaller cells to match your race duration?

That depends what you want to do with it! Some are more stable for carpark bashing, others are better for offorad and yet others will outperform both of those for sheer jump-and-bashability.

Best way to heat it up is to put it into boiling water and microwave it for, say, 30 seconds at a time.

Cool. I'd personally do a search to see what size monos and hydros are using .12 engines, then if you can't find more plans elsewhere, scale one of the free hydro pland down to suit. This should be easy enough with a good photocopier such as at a library or high street printing shop, Staples, Office Depot etc.

The Astec site that hpi_matrix_stock mentioned has a page of free hydro plans but I just discovered that they're designed for electrics. However they're quite small hulls and stuff like the water pickup is already sorted so shouldn't be too hard to convert to nitro, after all you're making it from plans so you should be able to get to a stage where you can do engine & running gear mockups to test for balance etc.

Yep, with something that small duiameter you'd need to be good at centering it. Just a hair's out of true and the motor's trash. You also need to undercut the insulation between the segments.

Hmm, carbs don't break from wear, they break because they've been forced when taking off or putting back on incorrectly. Hence the air leak, and the glue to try to stop it. He shoulda told you about the problems before he sold it to you and ooffered to pay for the new carb. There's no way he couldn't have known about it. Anyway, sorted now so have fun.

30,000 RPM is possible for a nitro. I'm sorry, I didn't spend ling in marine models so panther marine doesn't ring any bells. And as to your capacity / engine size question, I'm snookered there too so I guess unless somebody else can come up with some kind of a clue I'm out of this one for now! Good luck with your search.

The only free plans I could find on there were for hydros but it brought back memories; I watched a race with the real live "Pay 'n' Pak" gas turbine hydro in the USA in 1981!!! I did find a place where you can buy a plan & follow the online construction article for a decent competition mono suitable for a .21 engine. http://www.rcboatmodeler.com/RB/plans/fspb1000.asp Mike, is your engine really only 1.5cc? That's VERY small for any kind of monohull I'm guessing because you can't remember that it'll be around the .21 size (3.5cc) or maybe it's a .15 cubic inch (about 2.6-ish cc)? Anyway, I hope this has helped.

I do own my own company but I'm not an engineer. I did build my own model steam engine once and have always made and altered things mechanically. I can't remember ever NOT having a powered model of some kind in my childhood. I run a couple of trucks so the engineering knowledge is vital in the workshop, but my passion is physics and engineering is really just the practical application of that. Samij I'm flattered that you think I might be taking GCSE's or A levels, I've been driving trucks for 23 years!!! Sometimes when I see what the scientists are getting in the way of government grants as opposed to how hard I work for my living I think that's 22 years too long LOL Anyway, that's me. If I know something I post it, if I don't I keep my gob shut. Sometimes I'm wrong and that's OK too but I try not to post unless I'm sure of my facts. Cheers guys.